It is known to coat a chip with a protective layer, for example of a plastic, for protection against external influences. If the chip is, for example, a semiconductor chip with a sensor area, the sensor area, after having being coated with the protective layer, must be exposed again in order to ensure reliable operation of the sensor area and thus of the entire sensor.
From EP 1 602 625 B1, a semiconductor module and a method for producing it is known, the semiconductor module having a semiconductor sensor chip and a housing. The sensor chip has a sensor area in the housing and is electrically connected to at least one further component of the semiconductor module in the form of a semiconductor chip or of a passive component. The electrical connection, the further component and the non-sensitive areas of the sensor chip are embedded in a non-transparent plastic housing compound. The sensor area of the sensor chip, however, is actively connected to the environment via an opening in the non-transparent plastic housing compound, the opening exhibiting a laser stripping cone.
Stripping the plastic housing compound and thus exposing the sensor area is done by means of laser technology. Whereas the areal extent of the sensor area, and thus of the laser stripping cone, can be reliably adjusted using modern laser ablation technology, it is currently not possible to set the desired depth of the laser stripping cone accurately down to the sensor area or, respectively, it is not possible to reliably detect that the sensor area has been reached and to correspondingly stop the laser ablation. If the laser ablation is not stopped in time, the sensor area will be damaged. When the sensor area is damaged, correct operation of the entire semiconductor sensor chip is no longer guaranteed.